1. Annual summary of vital statistics-2002;Arias;Pediatrics,2003
2. SEER update of incidence and trends in pediatric malignancies: acute lymphoblastic leukemia;McNeil;Med Pediatr Oncol,2002
3. Friebert S 2009 http://www.nhpco.org
4. World Health Organization http://www.who.int/cancer/palliative/definition/en/ 2012